creating 3D mesh for some points in space

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lala
lala am 10 Feb. 2013
Beantwortet: Shivam Anand am 11 Mai 2022
So I have these points, A, B, C, ... in 3D. Their coordinates are denoted by x, y, z. For example point A has these coordinates: if x=2.5 and y=12, then z is 3, and B is x=4, y=3, and z=15; and so on.
So i created three arrays to show my points:
x=[2.5 4 6 18 9]; y=[12 3 7.5 1 10]; z=[3 15 16 8 11.5];
and i want to create a 3D mesh from my points (A, B, ...). There are total of 9 points.
I am able to create plot3 and/or scatter3 but not mesh :(
Ive spent already a full week on this and read many tutorials and such but i just get more confused and dont get it. Please help! Thanks!
lala-
  1 Kommentar
Kaixiang Wang
Kaixiang Wang am 30 Jan. 2017
A mesh for only nine points? And z is not a function of x and y? What sort of visual result are you expecting?

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Antworten (9)

Patrick Kalita
Patrick Kalita am 13 Feb. 2013
trimesh is probably what you want to use. You can also use delaunay to generate the triangulation matrix that trimesh requires.
x=[2.5 4 6 18 9];
y=[12 3 7.5 1 10];
z=[3 15 16 8 11.5];
tri = delaunay(x, y);
trimesh(tri, x, y, z);
  1 Kommentar
lala
lala am 18 Feb. 2013
Thanks. This is good but i think a smoother sruface like like surface mesh is what im looking for. Something to show at x and y coordinates, what is the z (distance.) I have about 9 z distances and basically want to find a good visual way. But thanks again.
L-

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Parker Hinton
Parker Hinton am 26 Mai 2017
Yes all, there is a solution, it has been stated. "Use griddata() or TriScatteredInterp to interpolate a grid of data from your points; then you can create a mesh from that."

Azzi Abdelmalek
Azzi Abdelmalek am 10 Feb. 2013
Bearbeitet: Azzi Abdelmalek am 10 Feb. 2013
You can't use mesh with your data. You will need more data. for example
x=[2.5 4 6 18 9];
y=[12 3 7.5 1 10];
[X,Y]=meshgrid(x,y)
% and for example
Z=X+Y
mesh(X,Y,Z)
% To understand, to create a mush plot with x=[1 2], and y=[ 10 20], you need
x=1,y=10
x=1,y=20,
x=2,y=10,
x=2,y=20
%to obtain these combinations we use
x=[1 2],
y=[ 10 20]
[X,Y]=meshgrid(x,y)
% find the corresponding z to each point
Z=cos(X+Y) % for example
mesh(X,Y,Z)
  1 Kommentar
lala
lala am 18 Feb. 2013
Thanks for explanation. But since my Z is not a function of X and Y, i guess mesh and meshgrid could not be useful.

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Walter Roberson
Walter Roberson am 11 Feb. 2013
Use griddata() or TriScatteredInterp to interpolate a grid of data from your points; then you can create a mesh from that.
Or you may wish to create a trimesh() once you have done a triangulation.

Benoit Botton
Benoit Botton am 4 Dez. 2014
Lala,
did you ever find a solution? I have the same issue

Bhuvan Varugu
Bhuvan Varugu am 14 Apr. 2015
I have the same issue. Please share some knowledge on this if you can?

fauer781
fauer781 am 7 Jan. 2017
Hi, I am in the same situation. Is there a solution?

Jaco Verster
Jaco Verster am 6 Jul. 2017
I had a similar problem - found a great solution here: https://www.mathworks.com/matlabcentral/fileexchange/8998-surface-fitting-using-gridfit

Shivam Anand
Shivam Anand am 11 Mai 2022
x=[32 20 67 1 98 34 57 65 24 82 47 55 8 51 13 14 18 30 37 39 10 33 21 26 38 81 83 60 95 22 17 5 72 46 99 52 12 25 96 29 70 85 43 69 19 78 97 31 89 53 2 91 48 71 61 15 36 84 94 50 11 80 6 7 49 74 9 88 40 79 27 68 73 64 63 59 86 23 35 58 45 28 100 42 93 87 16 90 41 66 54 92 77 4 62 76 75 56 3 44];
y=[96 75 24 9 83 49 27 77 3 23 17 31 40 13 7 52 51 21 98 47 64 79 78 91 44 16 15 100 84 99 63 68 70 30 54 76 97 73 33 5 88 8 71 66 62 25 60 42 72 45 18 11 28 59 89 65 10 55 69 81 12 26 20 95 87 41 74 50 93 22 43 90 14 34 82 35 56 38 80 32 1 57 6 36 37 61 29 58 2 48 4 46 67 53 92 86 94 19 39 85];
z=[55 31 11 45 83 36 86 49 15 57 42 46 8 94 88 47 54 81 98 41 32 35 56 85 9 89 37 60 23 62 67 100 78 76 73 80 10 20 68 34 77 93 1 63 53 12 22 99 91 40 84 24 33 3 43 19 92 97 6 82 64 25 26 79 95 4 44 58 5 21 70 29 65 87 96 90 51 14 18 2 72 28 71 39 52 7 27 59 50 61 48 30 66 69 17 13 74 16 75 38];
xlin = linspace(min(x), max(x), 100);
ylin = linspace(min(y), max(y), 100);
[X,Y] = meshgrid(xlin, ylin);
% Z = griddata(x,y,z,X,Y,'natural');
% Z = griddata(x,y,z,X,Y,'cubic');
Z = griddata(x,y,z,X,Y,'v4');
mesh(X,Y,Z)
axis tight; hold on
plot3(x,y,z,'.','MarkerSize',15)

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